Industrial Field of the Invention
The present invention relates to a starting motor fitted with an epicycle reduction gear for starting an internal combustion engine of an automobile or the like and more particularly to the improvement including means for preventing the outer end face of a flange from wearing off, the flange being fitted to an output shaft on the inner side plate of its internal gear.
Prior Art
FIG. 5 is a vertical sectional view of the principal part of a conventional starting motor of the sort fitted with an epicycle reduction gear. In FIG. 5, there is shown a magneto D.C. motor 1 as a driving motor comprising a yoke 2 with an end plate 3 incorporated into or fitted to the front end thereof; a pole iron core 4 composed of a permanent magnet attached to the yoke 2; an armature core 5 fitted into an armature coil 6 and fixed to a rotary shaft 7; a commutator 8 fixed to the rotary shaft 7; a rear bracket 9 attached to the yoke 2 and employed to support the rear end of the rotary shaft 7 through a bearing 10; and a brush 11.
The magneto D.C. motor 1 also includes a front bracket 12 attached to the yoke 2; an output shaft 13, a flange 14 provided at one end of the output shaft 13, the other end thereof being supported with the front bracket 12 through a sleeve bearing 15; a support hole 13a bored in the axis of the output shaft 13; a stopper 16 fitted to the output shaft 13 and used to stop a pinion 27 from moving toward the other end thereof; a sleeve bearing 17 fitted into the support hole 13a for receiving the end of the rotary shaft 7; and a steel ball 18 installed in between a tapered center hole 7a and a tapered center hole 13b provided at the bottom of the support hole 13a and used to stop the output shaft 13 toward the one end thereof.
The magneto D.C. motor still includes an epicycle reduction gear 19 comprising a sun gear 20 formed at the end of the rotary shaft 7; a plurality of planet gears 21 engaging with the sun gear 20 and supported with a support pin 22 fixed to the flange 14 through a sleeve bearing 23; an internal gear 24 composed of plastic material such as fiber reinforced plastics offering greater mechanical strength, supported with the front bracket 12, regulated to a fixed extent of revolution and used to let the rotating planet gears 21 revolve, the internal gear 24 supporting the one end of the output shaft 13 through a sleeve bearing 25.
The magneto D.C. motor further includes an overrunning clutch 26 helical-spline coupled to the output shaft 13 and used to support the pinion 27 so that the pinion 27 can transfer torque in one direction.
Numeral 28 indicates a steel washer applied between the flange 14 and the side plate 24a of the internal gear 24 and so arranged as to prevent the inner end face of the side plate 24a from wearing off.
FIGS. 3, 4 shows the internal gear 24 to which the washer 28 has been applied, wherein either revolution resulating projection 24c is fitted into a support groove 12a (see FIG. 5) provided in the front bracket 12 and used to stop the revolution of the internal gear 24. Each cutout for a through bolt 24d is used to couple the front bracket 12 to the yoke 2.
The operation of the aforesaid conventional apparatus is as follows: When the D.C. motor 1 is started, the rotary shaft 7 rotates and the sun gear 20 causes the planet gears 21 to rotate and engage with the fixed internal gear, whereby the torque is transmitted to the output shaft 13. At this time, the overrunning clutch 26 has been pushed forward by the operation of the magnetic switch of the starting motor through a shift lever (both are not shown) and, because its pinion 27 has engaged with the ring gear of the flywheel of the engine, the engine is started.
Problems to be Solved by the Invention
In the aforesaid conventional starting motor fitted with an epicycle reduction gear, the washer 28 is inserted between the flange 14 and the side plate of the internal gear 24 and the friction of the washer 28 tends to produce abnormal sound while the aforesaid motor is operated.
In addition to the aforesaid problem, an excessive washer 28 or no washer 28 maybe supplied by mistake.